Skin mark on Kitten

Hey everyone,

Hoping someone might be able to help with this. I am looking to adopt a new kitten, but we noticed a strange "spot" on her right shoulder.  I'm just concerned that it is a tumor or something that would affect her gait.  See attached for the picture.  The owner said that she noticed it a week or so after she was born, so I'm hoping its a birthmark?  Or ring worm?  I plan to consult a vet tomorrow but thought I would just see if anyone knew right away.

Any one who has seen this before, or knows what this is, I would greatly appreciate knowing what to do!

Thanks!! 

It's hard to tell from this photo what the mark could be. How old is the kitten? Let us know what the vet says!